Add several new aliases to git config.

* For changelog you should append the commit range. This could look like
  `v1.0.0...` to indicate from tag v1.0.0 to present (you need the
  periods)
* The restore command is setup so you (hopefully) can't reset your
  entire project. For example running `git restore` will just checkout
  the current branch again.  But `git restore filename` will checkout
  the given filename and thus restore it.
* Unlike the restore command, unstage will remove all files staged for
  commit if you don't specify a file. Generally this is what I want.  It
  does accept specific files though.